Propeller.



J. F. BALL.

PROPELLEB.

APPLIOATION rILnD M127, 1909.

Patented Aug. 31, 1909.

m'z'nsses; *221% f UNITED sTATEs PATENT OFFICE.

JOSEPH F. BALL, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR OF ONE-FOURTH TCHARLES C.

BILLs, oNE-roim'm To P. D. cU'rLER, AND FRANcIsco, CALIFORNIA.

PROPE ONE-FOURTH T0 FREDERICK W. BALL', OF SAN' LLER.

Letters Patent. Patonted Aug. 31, 1909.

Application filed April 27, 1909. Serial No. 492,440.

To a/ whom it may concem: le it known that I, J'su'rII F. BALL, acitizen of the United States, residing in the city and county of SanFrancisco and State of California, have invented new and usefullinprovemcnts in Propellers, of which the .following is a specification.

My invention relates to propellers.

llcretofore it has been considered a desideratuiu thatI thepropellerblades should' throw the water off centrifugally. I havedevised a propeller with blades of peculiar design curved on geometricallines so that the water is directed backward, more on lines parallelwith -the axis of the shaft, so as to get. a greater push against thebody of water and give additional speed to the boat.

'l`he invention consists of the parts and the construction andcon'ibination of parts as hereinafter more fully described and claimed,having reference to the accompanying drawings, iniwhich- Figure l is a.side elevation of the invention. Fig. 2 is a real' view. Fig. 3 is asection on X-X, Fig. 2. Fig. et is a section on Y-Y, Fig. 1..

lu the embodiment of the invention, A repi'esent's a propeller shaftprovided with two or more blades 2, and with the outer end of the shaftcontinued beyond the blades and tapei'ed and concaved to form a concavedconical projection 3. These'blades are set in such position to the shaftand are so fashioncd as to cause a congestion of the water toward thecenter of the wheel, thereby creating a greater pressure on the surfaceof the blades, and at'the same time sending or forcing the waterstraight back in the line of the axis of the propeller. The outer or"eX-treme points of the blades are Curved, as shown at 5, so that theseCurved ends lie substantially parallel to the, shaft. The rear edges 6of the blades are each curved before bending the fianges, in an are of asemicircle (see dotted lines, Fig. 2) and these rear ed es are higherthan the front Cutting edges o the blades, since'thelatter are transiversely dished, so that this transverse dish, taken with thelongitudinal dish formed by the curved ends 5, gives the appearance of'a cup when the propeller is spun rapidly; and

it is this cup which acts on the water and` forces it backward in theform of a column substantially in the line of the shaft. By forming theconcal project-ion 3 with the concaved sides, the 'void usually formedby pro}')ellers around the base of the blades is in part filled, andalso the concaved sides of the part 3 form defiecting surfaces for thereactance of the water forced inwardly by these dish-shaped blades.

I claim that curved blades at the extreme points, as shown, give abetter hold on the water for the blades, insuring less slip and greaterspeed.

l'laving thus described my invention, what l claim and desire to secureby Letters .Pat-

ent is- 1.. A propeller having a lurality of blades with their Operatingsur accs transversely dished, and also with the ends of the bladescurved backwardly to form ianges 'which are substantially parallel withthe axis of the propeller, and a conical extension on the hub of thepropeller beyond theblades, said cenie-al projection having'conczwedsides.`

2. A propeller having a plurality of blades with their. opcraftingsurfaces tral'isversely dished, and also with the ends of the blades;Curved baclnvardly to form tlanges which are substzntially parallelwith the axis of the propeller, the blades being' of-such shape that ifthe flanges and body were opened out into the same plane the backvedg-esV of the blades Would be approximately an are of a semi-circle.In testimony Whereof I have hereunto set my hand in presenceof twosubseribing witnesses.

JosEPH F. BALL.

